iUndelete preview never shows pictures.
To recover deleted photos, either pick simple volume recovery and make sure deleted files are included (bottom option), or pick the image recovery mode. You can put recovered pictures anywhere you like as long as you do not write them to the card you are recovering from.
Image recovery: http://www.diydatarecovery.nl/irecover_img_rec.htm
Simple volume recovery: http://www.diydatarecovery.nl/forum/index.php?topic=368.0